


Upside Down

by transdonatello (korrodere)



Category: Teenage Mutant Ninja Turtles - All Media Types
Genre: M/M, Trans Character, Turtlecest (TMNT), tcest
Language: English
Status: In-Progress
Published: 2021-03-14
Updated: 2021-03-14
Packaged: 2021-03-22 22:27:43
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,285
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/30045708
Author URL: https://archiveofourown.org/users/korrodere/pseuds/transdonatello
Summary: “And you thought I was gonna be the easy conversation, huh?” Don joked through his tears.“Foot in my mouth,” Raph agreed. “But I’m sure this would have happened eventually. Suppose it’s better to rip the bandage off now?”“Oh, my stars,” Don veiled his face in his hands. “I can just see me in my thirties, still wondering what the hell is wrong with me.”“Nothing’s wrong with you, Don. Get that out of your head right now.”--On the cusp of pubescence, Raph's younger siblings are going through some biological changes, and Raph, as a good big brother, wants to help them so they don't go through it alone as he had. What results is a lot more than anyone bargained for.*Content warning: some of the sex and gender wording within might be considered triggering. Please read with discretion.
Relationships: Donatello/Raphael (TMNT)
Comments: 2
Kudos: 8





	Upside Down

**Summary for the Chapter:**

> Raph sits Don down to have 'the talk'. It doesn't go as expected.

**Notes for the Chapter:**

> Be advised: lots of talk of pee and poop and genitals ahead.

His brother was really about to have ‘the talk’ with him. Leo and Mike had warned: it was quick, but kind of awkward, and a lot less stale than the talk Splinter had given them previously.

Don didn’t want to have this talk; he already knew the blah blah blah. He wanted to hide in his lab until Raph gave up, but he knew his brother better than that.

Raph was the eldest by over a year, at least according to Splinter's old adoption papers from the pet store. He went through his turtle puberty alone, and he was hellbent on making sure the others knew what was coming.

So there Don sat upon the hammock in Raph’s room, with Raph seated across the way on a beanbag chair.

“Now, I saved you for last,” Raph said, “because I figured you probably got everything sorted out, and this would be quick. But, if there’s anything you’re unsure about, hit me. I know Leo’s already started seeing changes, so I’m guessing you are too.”

Leo and Don were twins after all.

“Uh, yeah, no. I haven’t noticed anything,” Don said, scratching his head. “Maybe I’m a late bloomer?”

“Totally possible.” Raph shrugged. “But you haven’t noticed appetite increases, outbursts, rampant horniness?”

Don shook his head, mask tails fluttering behind him.

Taking a closer look, Raph noticed Don hadn’t started growing out as the others had. Maybe it’s because Leo was still fairly slim that he didn’t see it before? But even Mikey was bulking up, much as Raph had - he was merely awaiting his growth spurt. Don had grown, that was for sure, like a beanstalk. His limbs though were still slender, and his face still held a childlike pudge.

And then Don made an offhand comment that threw Raph completely for a loop.

“My penis still hasn’t even grown in. Isn’t that funny?” He said it with such a carefree laugh, but now Raph was staring at him like he’d developed a second face. “Uh, what?”

“You wanna run that by me again?”

“Y-You know, a penis? The long dangly bit that comes out when we pee? I’m envious; seems like you and Mike already got yours. Leo, I’m not sure about since he’s kind of quiet about that stuff.”

“D, uh. I don’t know how to tell you this, but we’ve all had our dicks since we were born. (Or, at least, I have. I guess I never asked the others about theirs….) They’re just, tucked away when we ain’t using them.” He motioned vaguely to the underside of his plastron.

“Right, like in a normal turtle’s cloaca….”*

“Right.”

“But you’ve had yours—?” His voice caught, thoughts spinning 1000 miles an hour.

“Since we were tots. Mike and I used to have pissing comps to see who could shoot the farthest.” He chuckled. “Least till Splinter caught us and made us stop.”

“M… Maybe something’s wrong with mine? I’ve never been able to release it.”

Raph scratched his head. “How do you pee, then?”

“Like, this. Sitting down.” Don gestured to his seated position. “Or I squat.”

“Like we did when we were kids. But you never stopped doing that?”

Don shook his head.

“You never had any sorta overwhelming feeling down there when you have to go, and it would just… drop?”

Another head shake.

“I mean,” Don said, “I get a full bladder feeling, but nothing else. And it goes away once I’ve gone.”

“Man,” Raph worried. “If we didn’t have Leo as sort of a guide point, I’d say maybe things are just different for ya.”

Don made a concerned noise and propped his head on his hands.

“Look, D. Now you can totally say no, but I’m really worried something might be wrong down there. Would it be ok if I checked?”

“Tit for tat?” Don jokingly asked. When Raph raised a confused eyebrow, he expounded, intonation nervously higher, “Can I, uh, see yours, too? Just for comparison’s sake?”

“Yeah, no prob.” Raph paused. “I’ll go first?”

Don swallowed. “Sure.”

Raph didn’t know why he suddenly felt self-conscious; he’d done dare-to-compares with Leo and Mike plenty of times over the years. He released a long exhale and let himself drop, separating his legs and slouching on the beanbag to provide Don a clearer look.

“It’s just, like that. Comes out when you need it (and sometimes when you don’t).”

Don’s mouth went dry. He slipped off the hammock to sit beside Raph. Why were his cheeks flushing?

Raph was monstrous, though proportionate for his overall size. He had a slit like Don did, which left Don even more confused.

“Just like that, huh?” Don quoted. “Now you’ve got me worried too.”

“Let’s see?” Raph urged gently, tucking himself away again. “Here, sit where it’s comfier.” He offered Don the beanbag.

In an imitation of his older brother, Don spread his legs to reveal his (albeit longer) slit, which was currently a little damp. He pulled it apart with his fingers.

“See? Nothing.”

“Try relaxing, see if you can feel anything go,” Raph suggested.

“I’m afraid I’m going to pee on your chair.”

Chuckling, Raph grabbed the tissue box from his bedside table and pitched it to Don, who took a wad and wedged it between his legs.

Don’s face screwed up in concentration as he tried releasing.

“No, try relaxing,” Raph repeated. “Like, I dunno, when you have a bad dump stuck in ya and you gotta stop clenching so it can pass.”

“What kind of poops do you have?”

Raph shrugged. “Big turtle, big poops. What can I say?”

“No wonder the toilet always gets clogged,” Don mumbled.

Why were they having this conversation?

He let out a sigh and tried to relax, tried to picture his penis dropping from his slit - but as he feared, all he felt was the urine trying to leave his bladder. He clenched before more than a few drops hit the tissues and cursed.

“No luck?” Raph asked.

“No,” he groaned and threw the tissues into the nearby waste bucket. “I don’t get what I’m doing wrong.”

“Maybe you need to coax it out the first time?” Raph made a motion with his fingers.

Don let out an embarrassed cough. “I’ve, I’ve tried that. It just makes me feel weird.”

“But there’s nothing there?”

“Not that I’ve been able to find. Which is why I figured it had to grow in or something.”

Raph placed a hand on his brother’s knee. “Mind if I just, take a peek?”

“Yeah, yeah. Sure.” Don wasn’t sure why his voice was so breathy, but he retracted his hands and leaned back. He bit back a squeak at feeling Raph’s calloused fingers spread him open.

“You okay?” Raph asked.

Don nodded, hand in front of his mouth.

One glance through and Raph immediately recognized the issue, thanks to the volume of porno mags he had consumed (though he would never admit such a folly, no sir. He was a Good Turtle). He knit his eyebrows together, trying to find the right words.

He couldn’t just well announce, 'hey, Don, I think you might be a girl.'

But that would explain so much: Don’s higher voice, his soft skin and thinner form, his broader hips (Raph was noting them just now, seeing Don spread out like this.), his lovely smell.

Wait, smell?

Raph removed his hands from his brother with a start and shook his head to clear those thoughts.

“You’re scaring me, Raph. Say something.”

How do you politely say, 'bro, you got a vagina and a clitoris? Ain’t you never seen a human female before?'

No, perhaps Don hadn’t. Maybe he was like Mikey, who turned his nose at that kind of stuff, or maybe he was gay? Or maybe he only appreciated the love of his dusty textbooks and schematics - he certainly swooned over those.

“Uh,” Raph said. “You want the good news or bad news?”

“What?” Don clamped his legs together and leaned forward in a startle.

“Uh, jeez, bro, (sis?)” Raph tried again. “Okay, so I know what the problem is, but I don’t know how you’re gonna take it.”

Don gave him a look that said, just spill already.

“You got lady bits, D. That’s why you can’t find yer dick. There ain’t one to be found.”

Silence.

“Come again?” Don finally asked.

“You’ve got the same stuff human women typically have,” Raph said awkwardly.

“…And how do you know this?”

Well, shoot. Goodbye Good Turtle denial. Raph got to his feet and pulled out one of his magazines from a shelf stuffed in a back corner. He opened to a tamer page and held it out for Don to see.

“Guy’s gotta have something to beat his meat to,” he mumbled, heading off what was sure to be Don’s next question.

“That,” Don said, chuckling uncomfortably and handing the magazine back to Raph, “that can’t be right. There’s gotta be a different explanation.”

“We could check those old adoption certs Pops kept?” Raph offered.

“Yeah, that’s a good idea.” His voice was coated in hysteria.

He set a brisk pace to Splinter’s room in the back of the dojo, Raph hot on his heels. They dug through a drawer in one of the dressers and found the envelope from the old pet store. Inside were four now-ragged pages detailing each of them.

First: box turtle, age 1 year, male. Mikey, undoubtedly.

Second: alligator snapping turtle, age 3 years. Raph.

Third: red-eared slider, age 2 years, male. Don let out a relieved sigh. Crisis averted.

“There’s still one more,” Raph warned.

Fuck.

Don slipped the last page to the front with a shaking hand.

Red-eared slider**, age two years, female. The font was faint, but there was definitely an FE there.

Don clamped a hand over a warbling sound escaping his mouth and collapsed to his knees. He stuffed the papers back in their envelope and flung the whole thing away from him. Raph managed to snatch it and tidy up the stack before tucking it back into the drawer.

He placed a hand on Don’s shoulder, unsure of what to say. It was a lot for him to process; he couldn’t imagine what was going through Don’s overthinking cranium.

“Do you think Dad knew?” Don croaked, breath heavy from trying to hold back a sob.

“Honestly, with that small font and his bad eyes, I’m not sure.” He paused. “But I hope not.”

“I mean,” Don continued, voice higher in his rising panic. “Why would you buy three male turtles and one female? That makes no sense!”

Raph could think of a reason why, though he wasn’t about to say it.

“Maybe it was an honest mistake or a mix-up at the shop?” Raph offered.

“My whole life as I know it, owed to a mix-up?” Don said to the floor, gripping his bandana tails in a fruitless attempt to curb his blooming existential crisis.

“No, D,” Raph stuttered, trying to correct his mistake. “Sorry, that’s not what I meant. I-I’m sorry. Come ‘ere.” He despised words. They were so easy to mess up. He held his arms out to his brother and pulled him in for a firm, stabilizing hug.

Don finally let himself go, ugly crying be damned.

“I’m gonna take you back to your room, okay?” Raph asked, picking Don up after receiving an affirming nod.

He inspected the area for the others before dashing to the bedroom hallway and ducking in through Don’s door. He kicked it shut and sat down with Don on his bed. The mattress sank under their combined weight.

“And you thought I was gonna be the easy conversation, huh?” Don joked through his tears.

“Foot in my mouth,” Raph agreed. “But I’m sure this would have happened eventually. Suppose it’s better to rip the bandage off now?”

“Oh, my stars,” Don veiled his face in his hands. “I can just see me in my thirties, still wondering what the hell is wrong with me.”

“Nothing’s wrong with you, Don. Get that out of your head right now.” Raph rubbed his brother’s decorated carapace.

“What am I going to tell the others?” Don asked in a fresh panic. “That I’m actually their sister? Do I need to start calling myself Donatella? They’re gonna be so weird about it. And what about Splinter? Is it better or worse that he did or didn’t know?”

Raph sighed and let the motormouth run its course.

“One step at a time, okay?” he soothed. “Nothing’s gotta change that you don’t want to. You’re still Don. If you want to be called our sister, we’ll call you that. If you want to stay our brother, then you’ll stay that.”

“You guys would baby me even more than you already do if you started seeing me as a girl,” Don moaned.

“We don’t baby you!” Raph protested.

Don gave him a deadpan stare, then led his eyes to their current arrangement of Raph clutching him in his arms.

“I’m comforting you, not babying,” Raph corrected, patting Don’s head.

Don sighed and relaxed against his brother’s torso. Truth be told he didn’t hate being comforted/babied/whatever, at least when it wasn’t meant to be demeaning. He quite enjoyed the attention, especially from Raph.

“You promise you won’t say anything to Leo or Mike?” Don asked.

“Cross my heart. If they ask, I’ll tell them they need to talk to you.”

“Thanks.”

Worn out from crying, Don closed his heavy eyelids. Something about Raph’s tone and hold left him more relaxed than usual; the tension he always carried between his shoulders faded and before he knew it, he nodded off.

**Notes for the Chapter:**

> *Is that how it works? I have no idea.  
> **I think Don's a softshell turtle in ROT (I've never watched it fully)? But I wanted him and Leo to be the same to add to the twins thing. Also I was alerted by the kind Kyabetsu that the turtles being sexed at the ages listed on their certs is not accurate. For now, lets just pretend the store was good at guessing ;)
> 
> \--
> 
> Thanks for reading! Feedback is welcome, especially if you note any grammatical or spelling mistakes. 
> 
> The next chapter will be about Don and Raph figuring out what's next.


End file.
